Process and apparatus for molding soap



3 Sheets-Sheet 1 R. CRA IG ETAL .PROCESS AND APPARATUS FOR MOLDING SOAP Filed Jan. 25, 1941 July 18, 1944.

INVENTORS; Robert Crai A Aggrence Seymourl-firber ATTORNEYS July 18, 1944. R. CRAIG ETAL' BROCESS AND APPARATUS FOR MOLDING SOAP 3 Sheets-S heet 2 Filed Jan. 25, 1941 km QM LNVENTORSP -Eo ert Crazy Laurence 5%:m0urHar'her ATTORNEYS July 18, 1944. R. CRAIG ETAL 2,354,000

PROCESS AND APPARATUS FOR MOLDING SOAP Filed Jan. 25, 1941 3 Sheets-Sheet 3 INVENTORS: Robert Crazy ATTORNEYS 'ing-t in: treatment.

. Patented July 18,

UNiTEDT STATES} PAT raocass AND APPARATUS roa MOLDING Robert Craig, Heswall, and Laurence Seymour Barber, Peter-borough, England; said Barber assignor' to Baker Perkins Limited,-Peterbo'rough, England, and said Craig assignor to Lever Brothers at Unilever Limited, Port Sunlight, England, a company of Great Britain Application January 25, 1941, 'Serial No. amass \In Great Britain January 26, 1,940

. 16 Claims. (01. 25-9) This invention-relates to an improved method I and apparatus for molding and cooling molten soap so as to produce small soap billets orcakes of a size and form suitable for the direct stamping of the soap into tablet form.

Methods and apparatus for moldin and cooling molten soap into the form of solidified cakes have been heretofore'proposed. They comprise broadly the filling of the molten soap into each of 7 which is the unequal shrinkage of the soapduring cooling with consequent distortion of the solidified billets. v I

One of the'objects of the present invention therefore is to provide an improved method and apparatus to reduce. or. overcome this unequal method may effectively be carried out comprises an endless conveyor or, drum carrying a continuous series of molds each having an open sidethrough which it is filled'and an opposite side or bottom formed by a plunger. To avoid the in'-.

clusion of air bubbles in the soap the plunger is yieldablyurged to a position at the commencement of the filling operation of each moldwhere it is flush with the open side of the mold so that there is no air present in the mold which'can be trapped in the soap. The amount of soap fed into each mold is controlled by a stop limiting-the extent to which the plungr can bedepressed and.

preferablythis stop is adjustable in position so that the amount led can be varied.

The open sides of the molds are covered in a progressive manner by means of a continuous band of stainless steelor other flexible non-corrosive material held firmly against: and-moving with-the molds so that the soap' is maintained under the pressure exerted by the plungers and at the same time access ofair is prevented. In

' order to prevent displacement of the soap by the shrinkage and to produce soap billets having a substantially uniform surface.

Another object of the invention is toprovide a method and means to avoid the inclusion of air bubbles in the soap during the filling of a mold.

' A further object of the invention is to provide means to facilitate'th'e removal of the soap from the mold without damage to the'soap surfaces.- The above and additional objects and features of the invention are accomplished by our improved method and apparatus as describedbrieily herebelow and in greater detail hereinafter.

Therimproved method comprises the steps of confining ae-portio'n of molten soap'to a desired subjecting the soap to pressure and chill shape lie soap while it'is thus subjected'to' pressure. More particularly, the-molten soap is fed under employing in succession both spraying and im-,

pressure into a mold against means providing a yielding resistance to avoid the inclusion of air bubbles in thefsoap during the filling of the mold. The filled mold is covered and the soap contained; therein subjected to pressure. .The moldis then chilled while the soap is thus subjected to pressure and until a thin outer shell of-solidifled soap is formed in the mold, the thickness of the shell being sufficient. to permit the molded soap to be removed from the mold without distortion. 1 The mold is then' uncovered and the soap billet ejected'and further subjected to a more gradual cool- 4 form" of apparatus or machine selected for D mber illustratint' means by whlchiour plunger during the interval between the filling oi the mold and the covering of theopen side, the

' pressure exerted by the plunger is preferably reduced or removed by suitable means during this interval. I

The soap in the molds should'becooledas rapidly as possible and this is preferably done by immersing the molds in a cooling liquid'such as brine or by spraying the cooling liquid on to the surfaces or the molds and the mold coveror by mersion.

To remove the billets from the drum a transfer wheel and conveyorarrangement is provided-to which the soap billets are discharged from'the molds. The transfer wheel receives theibillets v from the molds and transfersthem to a conveyor which is arranged to carry the billets away while. they are at the same time subjected. to further."

cooling. The conveyor may be so constructed that the billets are each supported by slats or other suitable supports and are air-cooled to a suitable temperature for stamping, for example a mean temperature of 30 to 35 C.

. For a better understanding of the invention reference is made to thefoll'owing detailed 'de- 'sc'ription to be read in connection-with.theaccompanying drawings, in which:

Figure 1 is tdiagramhratical illustration ofa 5 form of mums selected for purposes .of musflns the invention; 1

Figure 2 is'an'enlarsed view.- in, vert ical eleva- EN QFFI cE' f tion with parts broken away showing. details of the apparatus; and

Figure 3 is a sectional view of the apparatus taken substantially along. lines 3-3 of Figure 2. As shown'diagrammatlcally in Fig. 1 of. the drawings the apparatus selected for purposes of illustrating the invention comprises a rotatable drum I supported on trunnions 2 and having a continuous seriesof molds 3 arranged around its periphery. A nozzle '4 is provided at the filling station for feeding molten soap to the molds and a, flexible endless. stainless steel inetal band I is arranged progressively to cover the molds as they leave the filling station and to move with them to a position just short of the discharge,

2 station. At the discharge station the soap cakes prisesa' number of sections, as shown in Figs. 2 v

and 3, each carrying a series of molds at its periphery. The nozzle. 4 is hot water iacketed and has an outlet for each section of thedrum. The

outlets .of the nozzle through whichthe molten flanges 22 are supported from the stop is so that once set they will'always be correctlrpositioned in relation to the stop for any position of its the cam- IS without being depressed by soap pressure the pins 2| will engage under the flanges 22 and be guided downwardly by those flanges flanges 22. r

As-soon as the molds are covered by the stain- .until they engage the under -surface of the less steel band the piston rods are released from the flanges 22 and the springs I! tend .to push the pistons outwardly thereby applying pressure Y surface of the drum and the steel band is-maintained under tension by a tensioning pulley 21.

soap, enters the molds have the same dimensions as the molds. The nozzle facings fit closely around the circumference of the drum and are extended circumferentially so as to closely cover the molds at the filling station. The nozztl facing at the trailing or rear. side extends to a knife edge 10 and is. shaped to fit to the curvature of the steel band 5 where it passes around a supporting pulley II. The whole of the nozzle fitting is pivoted about an axis at l2 to enable the nozzle to be moved away from the drum for cleaning purposes.

The bottoms of the molds I are in the form of close-fitting plungers or pistons l3 which are urged toward the open side of the molds by springs I l cooperating with stirrups l5 secured to the drum surface.

In operation the molds approach the filling.

nozzles with'the pistons biased to the top of the molds by the springs i4 and heldin that position by a cam l6 engaging the ends of the piston rods I1. I As, the molds reach the filling station the piston rods I? move off the cam. RB and the pistons are retained in position by the pressure 18 to prevent the instantaneous filling of the molds. In this way the soap is maintained under pressure during the whole of the ruling of the molds voids in the soap. The pistons are pressed inwardly by the soap justable to vary the extent of the movement of the -.pistonsand therefore theamount of soap which is fed into the molds. If desired the means-for adjusting this stop may be so arranged in operation.

As the molds move away from the filling station' transverse pins v2| near the ends of the that they can be operated while the machine is a piston rods I! .move under flanges 22 which pre-' -vent the springs ll from urging the pistons outwardly until the open surfaces of the molds are covered by the stainless steel band 5. The

' which prevents the formation of air bubbles or Immediately after leaving the filling station the molds are sprayed with jets of cooling liquid issuing from nozzles 28 which eifects prelimi-' nary cooling of the soap.

This preliminary cooling continues until the molds are. immersed in cooling liquid contained a bath 29. The cooling liquid in the bath, which may be' the same as that issuing from the nozzles 28, may be brine and it may be maintamed at a low temperature by cooling coils im mersed in the 'liquid or the liquid may be drawn away from the bottomof the tank by a pump and passed through cooling coils back to the nozzles 28 and thence to the body of the liquid in the bath. When brinev or similar corrosive coolingliquid is employed, the bath and other parts of the machine which come into contact with the liquid should he made of corrosive-resistantmaterial such as stainless steel or mild steel clad with stainless steel or tin coated cast iron.

The stainless steel band 5 is. driven by its engagement with the surface of the drum and it remains in contact with the molds until the latter leave the cooling bath. Immediately before the band leaves the molds by passing around the pulley 3B, the pins 2i .on the piston rods move under flanges 3i which control the outward movement of the pistons in such manner that the soap is gradually ejected from the molds. The ejection of the soap is efl'ected by the springs It in conjunction with a cam bar 32 engaging the ends of the piston rods. The soap cakes 23 as they are ejected are received in pockets in the transfer wheel 6 formed by the fingers 34. The transfer wheel is drivenfrom the drum by means of gears and it has thesameperipheral speed as the drum. Ata point onthe transfer wheel diametrically opposite to that at which the cakes are received, the cakes are pushed .out of the pockets by a'cantilever pusher; rod 36 onthe conveyor 8. 1 I

- The conveyor is of the vertical chain link type andis fltted with rubbercovered pins, u,- :1

which support the cakes. -In order to carry out satisfactorily the transferoperation from the wheel 6 to the corfveyor '2 the transferiwheel as a whole is. caused to'travel inv an upward direction at the same speed as the conveyor 2 during the transfer operation by means of a cam 32 en cas g a follower- I! on the 'arm 40 which carthe centre of rotation of the drum I. The movements of the arm 40 also effect the movements of the pusher 35. Immediately the cake has beentransferred to the conveyor the transfer wheel moves back into its original position, During. the time the cakes are on the transfer wheel air is blown on to them from jets 4| which blows away any adherent cooling liquid and eflects a further degree of cooling of the soap. 7

The conveyor 3 may be arranged to pass the cakes to an air conditioning chamber prior to the final stamping operation; Further, the cakes may besubjected to additional cooling by means of an air blast; while they are on the conveyor and the conveyor may be so arranged as to turn .the cakes over at regular intervals during the cooling operation in order to make the shrinkage as uniform as possible and to prevent remelting of the soap at points of contact with the pins of the conveyor. The final cooling of the soap may be efiected after stamping and, as before, by means of air.

In the operation of the machine a pressure of about 1 lb.-/sq. in.'is used on the soap at thefilling nozzles and the temperatureof the soap at this point is normally maintained at about 70 C. The temperature is preferably the minimum temperature of about 2 C. These conditions,

such as temperature, pressure and time of cool-.

ing, may of course, be considerably varied without departing from the spirit of the invention.

The solidified shell of cooled soap formed on the tablets during the cooling in the molds has the form of an' outer layer of hard soap merging through layers '1 soap of increasing softness into'the still liquid soap inside the tablet. The thickness of the hard shell formed when the invention is carried out as described in the above example is approximately This thickness however varies with the operating conditions.

It will be apparent that by use of the machine herein described molten soap can be confined to a desired shape and subjected to pressure to maintain that shape during the chilling operation and until a solidified shell is formed. The cakes thus formed are removed and carried over a cooling conveyer where they are periodically turned and subjected to cooling air to complete the solidification thereof. During this latter cooling of the cakes the shape of the cakes is maintained without any appreciable uneven in the soap during the filling of the mold, and chilling the mold while the soap therein is maintained under pressure.

2. The method of molding molten" soap into billets and the like comprising forcing molten soap into a mold, resisting the introduction of the molten soap by a yieldinglforce to avoid the inclusion of'airbubbles in the soap during the filling of the mold, covering the filled mold, subjecting=the soap contained therein to resiliently exerted pressure that is substantially the same billets and the like comprising confining a por mally about two minutes and brine used has a I tion of molten soap to a desired shape, subjecting the soap to a continuously exerted resilient pressure to maintain the soap in such shape while solidifying, chilling the soap while thus subjected to said pressure to form at least a solidifled outer shell, removing the confining pressure, and further cooling the soap to complete solidification thereof.

5. Apparatus for molding molten soap into billets and the like comprising a mold, means shrinkage or the remelting of the solidified shell.

, While we have shown and described a particular form of apparatus by which the method can be carried out, it will be readily apparent that other apparatus or that many changes and variations of the apparatus disclosed can be-made and used to carry out the method without departing from the spirit of our invention. It will therefore be understood that the form of apparatus herein illustratedand described is intended to beillustrative ofthe invention only and, a

not as limiting the scope thereof.

We claim;

1. The method of molding molten soap into billets and the like comprising forcing molten" soap into amold, resisting the introduction of the molten soap by a continuously exerted resilient force to avoid the inclusion of air bubbles to feed molten soap into said mold, means to subject the soap contained in the mold to a continuously exerted resilient pressure during cooling, and means to. chill the soap while thus-subjected to pressure.

6. Apparatus for moldi g molten soap into billets and the like comfrising a mold, means to feed molten soap into, said mold, means to cover said mold, means to subject the molten soap confined in the mold to a continuously'exertedresilient pressure during cooling, means to cool the soap while thus subjected to pressure to form at least a solidified outer shell, and

means to'remove the billet of soap from the mold for further cooling.

7. Apparatus for molding molten soap into billets and the like and cooling the same comprising a mold having an open top and a'bottom member movable to a position substantially flush with the open top during both a filling of the mold with soap and a subsequent cooling thereof, means yieldingly biasing said bottom member to said position, means to feed molten soap under pressure into saidmoldagainst the force, of saidyieldable biased member, means to cover the top of the mold to confine the molten soap against the pressure exerted by said bottom member,

and means to chill the soapwhile thus subjected 0 pressure. a

8. Apparatus for molding molten'soap into billets'and the like and cooling the same comprising a mold having an open top and a bottom member movable toward a position substantially flush with the. open top during both-a filling of the mold with soap and a subsequent cooling thereof, means supplying a force tending to move said bottom member toward said position, a nozble to feed molten soap, means for, moving the mold to bring, the open top thereof into position adjacent said noz z'le for recepti'onoi soap against periphery of said drum to the yielding resistance of said bottom member, and means to cover said mold as the mold is moved away from said nozzle.

9. Apparatus for molding molten soap into billets and the like and cooling the same comprising a mold having an open top and a plunger bottom, means to yieldably urge said bottom toward a position substantially flush with said open top during a filling of the mold with soap and a subsequent cooling thereof, means to feed molten soap into said mold against the yielding pressure of saidbottom, means to cbver the open top of the 'mold when filled, and means to render ineffective the yielding pressure normally exerted by said plunger bottom during the covering of the mold.

10. Apparatus for molding molten soap into billets and the like comprising sin endless conveyor, a series of molds carried by said conveyor, means for filling each of said molds with molten soap, means to cover each mold, means to maintain the soap contained in the mold under a continuously exerted yielding pressure for a predetermined travel of the conveyor, means to chill the filled molds during such travel, means. to

Q,854,000 I T eject the chilled soap from the molds at the end said bottom, means to cover said mold, means to render said biasing means ineffective after the V filling operation-and until the mold is covered, means'to chill the mold, means touncover the mold after a predetermined chilling, and means to positively move said bottom to eject the soap billet from "the mold after the Y uncovering operation. V

12. Apparatus for molding molten 'soap into billets and the like and cooling the same comprising a rotatable drum, a series of molds ar- I ranged at the periphery of the drum and having an outer open side and an inner plimger bottom movable to 'a position substantially flush with said openside during a filling of the mold with soap and a subsequent chilling thereof, aspring biasingsaid plunger tending to move it toward said position during both the filling and cooling a,nozzle arranged closely adjacent the feed molten seep intooperation,

each in'old against the yielding resistance of the plunger bottom thereof, and a continuous flexible member arranged .to progressively cover. the molds as they move away from said nozzle.

13. Apparatus for molding molten soap into billets and the like and cooling the same comprising a rotatable drum, a series of molds arranged at the periphery of the drum and having an outer open side and an inner plunger bottom movable, to a position substantially fiush with said, open side; during-a filling of the mold with soap and a subsequent chilling thereof, a spring biasing said plunger tending to move it toward said position during both the fllling and cooling operation, a nozzle arranged closely adjacent t e periphery of said drum to feed moltensoap into each mold against the yielding resistance of the plunger bottom thereof, a continuous flexible member arranged to progressively cover the molds as they move away from, said nozzle, and means-for holding said plunger bottom against movement by said spring toward said open side after the filling operation and -until the mold has been covered. 4

14. Apparatus'for molding molten soap into billets and, the like and cooling the same comprising a rotatable drum, a series of molds arranged at the periphery of the drum and having an outer open side and an inner plunger bottom movable to a position'substantially flush with said-open side during a filling of the mold with soap and a subsequent chilling thereof, a spring biasing said plunger tending to move it toward said position during both the filling and. coolin operation, a nozzle arranged closely adjacent the periphery of said d'rum'to feed molten soap into each mold against the yielding resistance .of the plunger bottom thereof, a continuous flexible member arranged to progressively cover the molds. as they move away from said nozzle, means to chill the molds, means to remove the covering member [after a predetermined chilling, and

means for positively moving the plunger bottom toward said-open side after removal of said covering member to eject the soap billets.

15. Apparatus for molding molten soap into billets and the like comprising means including a series of molds'and means to eject the soap billets from said molds when at least partly solidifled, a conveyor, and transfer means including a serie of pockets adapted to receive the billets as they are ejected and move them to 'the conveyor,

and. means to cool and further solidify'the billets while they are in said pockets.

-16. Apparatus for molding molten soap into billets and the like and cooling the same comprising a rotatable drum, 9. series of molds ar-' ranged at the periphery of the drum and having an outer open side and an inner plunger bottom movable to a position substantially fiush with said open side during a filling of the mold with soap and a subsequent chilling thereof, a spring 1 biasing said plunger tending to move it toward said position during both the filling and cooling periphery of said drum to feed molten soap into operation, a nozzle arranged closely adjacent the each, mold against the yielding resistanceof the plunger bottom. thereof, means to'progressively coverthe molds for a predetermined travel'during rotation of the drum, means to render said yelding resistance ineffective during the covering of the mold, means to chill the molds while covered and while the soap therein is subjected to a continuously exerted resilient force, a conveyor, a transfer wheel disposed between said drum and said conveyor haying pockets to receive the billets, means to eject the formed billets from said molds, and means for periodically moving said transfer wheel in the direction of drum rotation to receive an ejected billet and deliver a billet previously received to said conveyor.

. ROBERT CRAIG. I

MUQENCE SEYMOUR BARBER. 

